how to find the unique column(s) in a table

I am a user of Teradata, and not a developer. I run the select statement to do my work. I believe that each table has a unique column (like 1 column SSN), or a unique combintion of coumns(like 4 columns Firstname, Lastname, DOB, ZIPCODE). I need the unique columns to connect different tables(joins). Quite often, I work on tables that have hundreds of columns, and I do not know what is the unique column(s) of that table.

How to find the unique column(s) in a table? The statement (show select * from table) might help, but it returns a lot of information, and I do not know how to get the answer to my question.